Player ID and control about it

Hi,
i make a idle game and i want to have a different ID for every Player.
E.g. I give the Player #104321 100M Coins.
How is that possible? And are there any free solutions or must i have a server for money?
Thanks!

There’s several popular networking API’s. How exactly you do what you’re asking depends on which networking API you’re using, which you haven’t mentioned. If you haven’t chosen one yet, I’d suggest trying out a few as a first step.

OK,
first of all, thank you for your responsive. I’ve never done everything with networking API, so what and how I have to do it?

Take a look at the documentation for one of the available networking API’s, and any tutorials for them. MLAPI, Mirror, and Photon seem like the most popular. MLAPI is the official Unity supported API. Mirror is an updated fork of the last Unity supported API (called Unet).